National Center for Zoonotic

Atlanta, GA, United States

National Center for Zoonotic

Atlanta, GA, United States
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Elmore S.A.,Colorado State University | Jones J.L.,National Center for Zoonotic | Conrad P.A.,University of California at Davis | Patton S.,University of Tennessee at Knoxville | And 2 more authors.
Trends in Parasitology | Year: 2010

Toxoplasma gondii is a parasite of birds and mammals. Cats are the only definitive host and thus the only source of infective oocysts, but other mammals and birds can develop tissue cysts. Although feline infections are typically asymptomatic, infection during human pregnancy can cause severe disease in the fetus. Cat owners can reduce their pets' exposure risk by keeping all cats indoors and not feeding them raw meat. Humans usually become infected through ingestion of oocyst-contaminated soil and water, tissue cysts in undercooked meat, or congenitally. Because of their fastidious nature, the passing of non-infective oocysts, and the short duration of oocyst shedding, direct contact with cats is not thought to be a primary risk for human infection. © 2010 Elsevier Ltd.

Xiao L.,National Center for Zoonotic
Experimental Parasitology | Year: 2010

Molecular tools have been developed to detect and differentiate Cryptosporidium at the species/genotype and subtype levels. These tools have been increasingly used in characterizing the transmission of Cryptosporidium spp. in humans and animals. Results of these molecular epidemiologic studies have led to better appreciation of the public health importance of Cryptosporidium species/genotypes in various animals and improved understanding of infection sources in humans. Geographic, seasonal and socioeconomic differences in the distribution of Cryptosporidium spp. in humans have been identified, and have been attributed to differences in infection sources and transmission routes. The transmission of C. parvum in humans is mostly anthroponotic in developing countries, with zoonotic infections play an important role in developed countries. Species of Cryptosporidium and subtype families of C. hominis have been shown to induce different clinical manifestations and have different potential to cause outbreaks. The wide use of a new generation of genotyping and subtyping tools in well designed epidemiologic studies should lead to a more in-depth understanding of the epidemiology of cryptosporidiosis in humans and animals.

Lanciotti R.S.,Centers for Disease Control and Prevention | Lambert A.J.,Centers for Disease Control and Prevention | Lambert A.J.,National Center for Zoonotic
American Journal of Tropical Medicine and Hygiene | Year: 2016

In December 2013, chikungunya virus (CHIKV) was isolated for the first time in the Western Hemisphere (WH) during an epidemic on the island of St. Martin. Subsequently, the virus has spread to 42 countries or territories in the Caribbean, Central, South, and North America. In this study, we have determined the full genomic sequences of 29 temporally and geographically diverse CHIKV strains from 16 countries of the WH. Phylogenetic analyses revealed minimal evolution among compared emergent CHIKV strains of the New World. © Copyright 2016 by The American Society of Tropical Medicine and Hygiene.

Lucio-Forster A.,Cornell University | Griffiths J.K.,Tufts University | Cama V.A.,National Center for Zoonotic | Xiao L.,National Center for Zoonotic | Bowman D.D.,Cornell University
Trends in Parasitology | Year: 2010

The role of dogs and cats in human cryptosporidiosis has been the focus of much attention. Studies in which genotyping of Cryptospiridium oocysts in feces of dogs and cats have been successful and have demonstrated that most infections in these animals are caused by host-specific C. canis and C. felis, respectively. Most human cases of cryptosporidiosis are associated with C. hominis and C. parvum; C. canis and C. felis are responsible for only a small number of cases. Thus, molecular epidemiologic studies support the contention that the risk of zoonotic transmission of Cryptosporidium spp. from pet cats and dogs is low. Veterinarians can inform their clients of this minimal risk, but nevertheless advise them to minimize contact with pet cat and dog feces. © 2010 Elsevier Ltd.

Ballweber L.R.,Colorado State University | Xiao L.,National Center for Zoonotic | Bowman D.D.,Cornell University | Kahn G.,National Center for Zoonotic | Cama V.A.,National Center for Zoonotic
Trends in Parasitology | Year: 2010

Molecular data have defined seven genetic Assemblages of Giardia duodenalis, named A-G. Humans are infected with Assemblages A and B, dogs primarily with C and D, and cats with F. Assemblage A has been subclassified into subtypes A-I to A-IV: A-I has been reported in humans and animals, A-II in humans, and A-III and IV exclusively in animals. Assemblage B has broad host specificity infecting humans and animals. Recently, small numbers of dogs and cats have been reported to also carry Assemblages A-I or B. Because these genotypes are found primarily in humans, and no comprehensive studies to address zoonotic transmission of G. duodenalis are yet available, the potential role of dogs and cats cannot be conclusively excluded.

Luis A.D.,Pennsylvania State University | Douglass R.J.,Montana Tech of the University of Montana | Mills J.N.,National Center for Zoonotic | Bjornstad O.N.,Pennsylvania State University
Journal of Animal Ecology | Year: 2010

1. Since Sin Nombre virus was discovered in the U.S. in 1993, longitudinal studies of the rodent reservoir host, the deer mouse (Peromyscus maniculatus) have demonstrated a qualitative correlation among mouse population dynamics and risk of hantavirus pulmonary syndrome (HPS) in humans, indicating the importance of understanding deer mouse population dynamics for evaluating risk of HPS. 2. Using capture-mark-recapture statistical methods on a 15-year data set from Montana, we estimated deer mouse survival, maturation and recruitment rates and tested the relative importance of seasonality, population density and local climate in explaining temporal variation in deer mouse demography. 3. From these estimates, we designed a population model to simulate deer mouse population dynamics given climatic variables and compared the model to observed patterns. 4. Month, precipitation 5 months previously, temperature 5 months previously and to a lesser extent precipitation and temperature in the current month, were important in determining deer mouse survival. Month, the sum of precipitation over the last 4 months, and the sum of the temperature over the last 4 months were important in determining recruitment rates. Survival was more important in determining the growth rate of the population than recruitment. 5. While climatic drivers appear to have a complex influence on dynamics, our forecasts were good. Our quantitative model may allow public health officials to better predict increased human risk frombasic climatic data. ©2009 The Authors. Journal compilation ©2009 British Ecological Society.

Wright J.G.,National Center for Immunization and Respiratory Diseases | Quinn C.P.,National Center for Immunization and Respiratory Diseases | Shadomy S.,National Center for Zoonotic | Messonnier N.,National Center for Immunization and Respiratory Diseases
Morbidity and Mortality Weekly Report | Year: 2010

These recommendations from the Advisory Committee on Immunization Practices (ACIP) update the previous recommendations for anthrax vaccine adsorbed (AVA) (CDC. Use of anthrax vaccine in the United States: Recommendations of the Advisory Committee on Immunization Practices [ACIP]. MMWR 2000;49:1-20; CDC. Use of anthrax vaccine in response to terrorism: supplemental recommendations of the Advisory Committee on Immunization Practices [ACIP]. MMWR 2002;51:1024-6) and reflect the status of anthrax vaccine supplies in the United States. This statement 1) provides updated information on anthrax epidemiology; 2) summarizes the evidence regarding the effectiveness and efficacy, immunogenicity, and safety of AVA; 3) provides recommendations for pre-event and preexposure use of AVA; and 4) provides recommendations for postexposure use of AVA. In certain instances, recommendations that did not change were clarified. No new licensed anthrax vaccines are presented. Substantial changes to these recommendations include the following: 1) reducing the number of doses required to complete the pre-event and preexposure primary series from 6 doses to 5 doses, 2) recommending intramuscular rather than subcutaneous AVA administration for preexposure use, 3) recommending AVA as a component of postexposure prophylaxis in pregnant women exposed to aerosolized Bacillus anthracis spores, 4) providing guidance regarding preexposure vaccination of emergency and other responder organizations under the direction of an occupational health program, and 5) recommending 60 days of antimicrobial prophylaxis in conjunction with 3 doses of AVA for optimal protection of previously unvaccinated persons after exposure to aerosolized B. anthracis spores.

Jones J.L.,National Center for Zoonotic | Dubey J.P.,U.S. Department of Agriculture
Experimental Parasitology | Year: 2010

Humans become infected with Toxoplasma gondii mainly by ingesting uncooked meat containing viable tissue cysts or by ingesting food or water contaminated with oocysts from the feces of infected cats. Circumstantial evidence suggests that oocyst-induced infections in humans are clinically more severe than tissue cyst-acquired infections. Until recently, waterborne transmission of T. gondii was considered uncommon, but a large human outbreak linked to contamination of a municipal water reservoir in Canada by wild felids and the widespread infection of marine mammals in the USA provided reasons to question this view. The present paper examines the possible importance of T. gondii transmission by water.

Harris J.R.,National Center for Zoonotic | Neil K.P.,National Center for Zoonotic | Behravesh C.B.,National Center for Zoonotic | Sotir M.J.,National Center for Zoonotic | Angulo F.J.,National Center for Zoonotic
Clinical Infectious Diseases | Year: 2010

The federal ban in the United States on the sale of turtles with shell lengths <4 inches that was established in 1975 has reduced the number of turtle-associated human Salmonella infections during subsequent years, especially among children. Although numerous sporadic turtle-associated Salmonella infections in humans have been reported since the ban went into effect, outbreaks were not reported until recently. Since 2006, 3 multistate outbreaks of turtle-associated Salmonella infections have been documented in the United States. This review examines the history of turtle-associated human Salmonella infections in the United States and discusses reasons why an increase in turtle-associated salmonellosis may be occurring and how challenges in enforcement of the ban affect disease control. Additional steps should be considered by the public health community, state governments, and enforcement agencies to prevent turtle-associated Salmonella infections in humans.

Niwa H.,Equine Research Institute | Lasker B.A.,National Center for Zoonotic
Antimicrobial Agents and Chemotherapy | Year: 2010

The mutant prevention concentration (MPC) for ciprofloxacin was determined for two Rhodococcus equi strains. The MPC for both strains was 32 μg/ml, which is above the peak serum concentration of ciprofloxacin obtainable by oral administration in humans. Nine single nucleotide changes corresponding to eight amino acid substitutions in the quinolone resistance-determining regions of DNA gyrase subunits A and B were characterized. Only mutants with amino acid changes in Ser-83 of GyrA were highly resistant (≥64 μg/ml). Our results suggest that ciprofloxacin monotherapy against R. equi infection may result in the emergence of ciprofloxacin-resistant mutants. Copyright © 2010, American Society for Microbiology. All Rights Reserved.

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